Configuration

If defined before including qiskit.h, the header files will define all of symbols in a mode safe for use with Python extension modules. This means that all API functions will evaluate to function-pointer dereferences from a lookup table.

This is a user-defined macro and not defined by Qiskit itself.

int qk_import(void)

Import the Qiskit C API from the Python-space qiskit package.

You must call this once per compilation unit, before attempting to call any C API functions. Failure to do so will typically result in null-pointer dereferences at runtime.

You typically will want to do this inside your PyInit_* module initialization function. For example, in my_extension.c:

#define QISKIT_PYTHON_EXTENSION
#include <Python.h>
#include <qiskit.h>

static struct PyModuleDef my_extension_mod = {
   .m_base = PyModuleDef_HEAD_INIT,
   .m_name = "my_extension",
};

PyMODINIT_FUNC PyInit_my_extension(void) {
   if (qk_import() < 0) {
      return NULL;
   }
   return PyModuleDef_Init(&my_extension_mod);
}

This function is only defined when QISKIT_PYTHON_EXTENSION was defined prior to including qiskit.h.

Returns

0 on success, negative on failure.